New Zealand PM brushes off dirty tricks row in TV debate

New Zealand Prime Minister John Key speaks to students of Taratahi Agricultural School in Masterton during an election campaign event on August 20, 2014 (AFP Photo/Marty Melville)

Wellington (AFP) - Prime Minister John Key dismissed allegations of dirty tricks in the New Zealand election campaign as a "distraction" Thursday during his first televised debate with opposition leader Labour Party David Cunliffe.

The campaign so far has been dominated by a newly-published book, which cites emails hacked from the computer of a right-wing blogger to allege government figures waged a dirty tricks campaign to smear opponents.

Key, whose conservative National Party is leading in opinion polls ahead of the September 20 vote, said he intended to concentrate on issues such as the economy rather than claims of smear tactics.

"If David thinks this is the really big issue of the campaign, a sideshow and a bit of muckraking, then he's missing the point," he said. "People care about whether they have a job, about the education system."

Cunliffe used the debate to accuse Key of "wilful blindness" about the allegations, which involve one of his former staffers and a senior minister.

"New Zealanders have worked out by now that John isn't going to be giving them answers to the questions that they want to hear, the authorities are now investigating.

"New Zealanders will make up their own minds about the lack of frankness from him."

Police confirmed Thursday that they were investigating a complaint from blogger Cameron Slater about his leaked emails appeared in the book "Dirty Politics" by left-wing author Nicky Hager.

Key, who is seeking a third term in office, has brushed aside the allegations, labelling them "a left-wing conspiracy theory".

The tactic appeared to work for him in the debate, with 61 percent of voters in an online poll run by broadcaster TVNZ backing him as the winner compared to 39 percent for Cunliffe.

Key said he offered "strong and stable leadership" which had helped the New Zealand economy prosper after the shocks of the Global Financial Crisis and a devastating earthquake in Christchurch in 2011.

He also said he hoped that tax cuts would be implemented if he won a third term but would not give a solid commitment.

Cunliffe said he would introduce measures to make housing more affordable and ruled out re-nationalising state assets that Key has sold off during his six years in office.

Key currently governs with the support of a handful of minor parties but some polls suggest he could govern in his own right after this election, a situation unprecedented since New Zealand adopted a German-style mixed-member proportional (MMP) electoral system in 1996.

Key and Cunliffe will hold another televised debate on September 17, just three days out from the election.